CN106092263A - A kind of experiment high precision wireless numeral water depth sensor system - Google Patents

Abstract

The invention discloses a high-precision wireless digital water depth sensor system for experiments, which includes a host and a slave. The slave includes a sensitive element, a capacitor digital-to-analog conversion module and a slave wireless communication module. The sensitive element is measured through a parallel plate capacitor structure. The capacitance value of the water is sent to the host through the capacitance digital-to-analog conversion module and the slave wireless communication module in turn; the host obtains the water depth of the measured water according to the capacitance digital signal. The invention has the following advantages: high measurement accuracy, fast measurement speed, and can be used for water depth detection of fluctuating and unstable water flow; only one metal wire is in contact with water, and has little influence on water flow.

Description

A High Precision Wireless Digital Water Depth Sensor System for Experiment

technical field

The invention relates to the fields of public safety and water conservancy, in particular to an experimental high-precision wireless digital water depth sensor system.

Background technique

Continuous and accurate measurement of water depth is required in many scientific experiments (especially in fields such as hydraulics). Various water depth sensors currently available sometimes cannot meet the experimental requirements. Traditional water level probes need to rely on mechanical movement to achieve measurement, the measurement speed is slow, and when the water surface fluctuates greatly (such as rainfall experiments), large measurement errors will occur. Ultrasonic liquid level detectors have limited precision. Generally, they can only reach the centimeter level, and a few can reach the millimeter level, which cannot meet the requirements of precise experiments. The laser ranging detector itself has high precision, but due to the high transparency of water, the effect is not good when used for bathymetry. The pressure sensor is greatly affected by the ambient temperature and air pressure, so the accuracy is limited, and the use of some occasions that do not meet the static pressure distribution will lead to measurement errors (for example, raindrops in the rainfall experiment will cause additional impact pressure, resulting in the pressure sensor The water depth of the measured value reversed is too large). Capacitive water depth sensors require contact measurements, which may affect the flow field in experiments involving water flow, and additional errors due to contact angle hysteresis. In addition, existing water depth sensors have other disadvantages. At present, most water depth sensors output analog signals, which require analog-to-digital conversion to connect to a computer for automatic data collection and processing, and secondary errors will inevitably occur during the analog-to-digital conversion process. Moreover, analog signals are susceptible to interference during long-distance transmission, resulting in data errors. In order to solve these problems, digitalization of water depth sensors is required. In some large-scale hydraulic experiments, it is necessary to arrange a large number of sensors at different positions in the tank and collect data at the same time. Existing water depth sensors mostly use wired transmission, which requires laying a large number of cables, which is time-consuming and laborious, and may cause safety hazards to experimenters (stumbling over cables). In addition, some experiments that need to be carried out in a closed environment (such as experiments that need to be carried out under special conditions such as high voltage/low voltage) do not allow cables to be drawn out or lead out cables will increase engineering difficulty. In order to solve these problems, water depth sensors need to be wireless.

Contents of the invention

The present invention aims to solve at least one of the above-mentioned technical problems.

To this end, an object of the present invention is to propose a high-precision wireless digital water depth sensor system for experiments.

In order to achieve the above object, an embodiment of the present invention discloses a high-precision wireless digital water depth sensor system for experiments, including: a slave, the slave includes a sensitive element, a capacitance digital-to-analog conversion module, and a slave wireless communication module. The sensitive element includes an insulating container, a metal plate fixed on the outer wall of the insulating container, and a metal wire inserted into the inside of the insulating container, one end of the metal wire is less than a preset distance from the inner bottom wall of the insulating container, and the Both the metal wire and the electrode plate are connected to the capacitance digital-to-analog conversion module; the capacitance digital-to-analog conversion module is used to connect the metal wire and the electrode The capacitance value between the boards is converted into a capacitance digital signal, and the capacitance digital signal is sent to the slave wireless communication module; the slave wireless communication module is used to send the capacitance digital signal; the host, the host It includes a host communication module and a computer, the host communication module is used to receive the capacitance digital signal sent by the slave communication module, the computer is connected to the host communication module, and is used to obtain the capacitance digital signal according to the capacitance digital signal. Describe the water depth of the measured water.

The experimental high-precision wireless digital water depth sensor system according to the embodiment of the present invention has high measurement accuracy and fast measurement speed, and can be used for water depth detection of fluctuating and unstable water flows; only one metal wire is in contact with water, and has little influence on water flow .

In addition, the experimental high-precision wireless digital water depth sensor system according to the above-mentioned embodiments of the present invention may also have the following additional technical features:

Further, a hydrophobic coating is coated on the inner side wall of the insulating container corresponding to the metal plate.

Further, the hydrophobic coating is _SiO2 nano coating.

Further, the metal plate is a red copper plate.

Further, the preset distance is 5mm.

Further, the capacitance digital-to-analog conversion module includes a reference capacitance and a capacitance-to-digital conversion chip, the metal wire and the metal plate are connected to the capacitance-to-digital conversion chip, the reference capacitance is a monolithic capacitance, and the capacitance The digital conversion chip is the PCAP01 capacitance-to-digital conversion chip of acam company in Germany.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and comprehensible from the description of the embodiments in conjunction with the following drawings, wherein:

Fig. 1 is the structural representation of the experimental high-precision wireless digital water depth sensor system of an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of a sensitive element of an embodiment of the present invention;

FIG. 3 is a schematic diagram of a circuit structure of a slave according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a circuit structure of a host computer according to an embodiment of the present invention;

Fig. 5 is a test result diagram of an embodiment of the present invention.

detailed description

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

In describing the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", " The orientations or positional relationships indicated by "vertical", "horizontal", "top", "bottom", "inner" and "outer" are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and Simplified descriptions, rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and thus should not be construed as limiting the invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and should not be understood as indicating or implying relative importance.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it may be mechanically connected or electrically connected; it may be directly connected or indirectly connected through an intermediary, and it may be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

These and other aspects of embodiments of the invention will become apparent with reference to the following description and drawings. In these descriptions and drawings, some specific implementations of the embodiments of the present invention are specifically disclosed to represent some ways of implementing the principles of the embodiments of the present invention, but it should be understood that the scope of the embodiments of the present invention is not limited by this limit. On the contrary, the embodiments of the present invention include all changes, modifications and equivalents coming within the spirit and scope of the appended claims.

The experimental high-precision wireless digital water depth sensor system according to the embodiment of the present invention will be described below with reference to the accompanying drawings.

Please refer to Figure 1, a high-precision wireless digital water depth sensor system for experiments, including a slave and a host. Please refer to FIG. 2 , the slave includes a sensitive element 103 , a capacitive digital-to-analog conversion module 104 and a slave wireless communication module 105 . The host includes a host wireless communication module 101 and a computer 102 .

Please refer to FIG. 2 , the sensitive element 103 includes an insulating container 107 , a metal plate 108 fixed on the outer wall of the insulating container 107 and a metal wire 109 inserted into the insulating container 107 . One end of the metal wire 109 is less than a preset distance from the inner bottom wall of the insulating container 107 .

Specifically, the metal plate 108 is pasted on the outside of the side wall of the insulating container 107 to form a polar plate; the metal wire 109 is inserted into the insulating container 107 near the bottom wall, and the measured water introduced into the insulating container 107 forms another polar plate; thus , the metal plate 108, the metal wire 109 and the water to be measured form a parallel plate capacitor, and the insulating container 107 constitutes a capacitive medium. When the water depth is not very small (less than 5mm), the capacitance value of the capacitor has a significant linear function relationship with the water depth, so the capacitance value can be used to reflect the water depth.

The capacitance digital-to-analog conversion module 104 is connected to the metal wire 109 and the metal plate 108 , converts the capacitance value between the metal wire 109 and the electrode plate 108 into a capacitance digital signal, and sends the capacitance digital signal to the slave wireless communication module 105 .

The slave wireless communication module 105 sends the capacitance digital signal to the host wireless communication module 105, and the host wireless communication module 105 transmits the capacitance digital signal to the computer 102, and the computer finally obtains the water depth of the measured water according to the capacitance digital signal.

In one embodiment of the present invention, the inner wall of the insulating container 107 corresponding to the metal plate 108 is coated with a hydrophobic coating 111 to reduce additional errors caused by contact angle hysteresis. Preferably, the hydrophobic coating 111 is a SiO ₂ nano coating, which can greatly reduce the additional error caused by contact angle hysteresis.

In one embodiment of the present invention, the metal plate 108 is a red copper plate, which has good electrical conductivity and improves measurement accuracy.

In one embodiment of the present invention, the preset distance (the distance between the lower end of the metal wire 109 and the inner bottom wall of the insulating container 107) is 5mm. It should be noted that the lower end of the metal wire 109 can also contact the inner bottom wall of the insulating container 107 .

Please refer to FIG. 3 , in an embodiment of the present invention, the capacitance-to-digital conversion module 104 includes a reference capacitance 113 and a capacitance-to-digital conversion chip 112 . The slave wireless communication module 105 includes a wireless communication microcontroller 114 , an antenna 115 and an auxiliary component 116 . The slave machine also includes a power module 106 , and the power module 106 includes a battery box 117 , a switch 118 , a voltage stabilizing module 119 and a voltage stabilizing module 120 . Wherein, the capacitance-to-digital conversion chip 112 is connected to the sensitive element 103 , the reference capacitance 113 , the wireless communication single-chip microcomputer 114 and the voltage stabilizing module 119 respectively. In an example of the present invention, the capacitance-to-digital conversion chip 112 adopts the PCAP01 capacitance-to-digital conversion chip of acam company in Germany, which can measure the capacitance value of a capacitor and obtain the digital value directly. The reference capacitor 113 adopts a monolithic capacitor to reduce noise as much as possible. The auxiliary component 116 is respectively connected to the wireless communication microcontroller 114 , the antenna 115 and the voltage stabilizing module 120 . The wireless communication single-chip microcomputer 114 adopts the CC2530 wireless system-on-chip (SoC) solution of the Texas Instruments company of the United States, and this chip can realize the Zigbee wireless network communication function. Through software programming, the wireless communication single-chip microcomputer 114 can operate the capacitance-to-digital conversion chip 112 to perform capacitance measurement, read the measurement data and send it to the host through the antenna 115 . The auxiliary component 116 includes a crystal oscillator to ensure the normal operation of the single-chip microcomputer 114 and the antenna 115, and an LED light is used to indicate the working state of the single-chip microcomputer. The power module 106 includes a battery box 117 , a switch 118 , and voltage stabilizing modules 119 and 120 to provide stable power for the capacitance-to-digital conversion module 104 and the slave wireless communication module 105 .

Please refer to FIG. 4 , in an embodiment of the present invention, the host wireless communication module 101 includes a wireless communication microcontroller 117 , an antenna 118 , an auxiliary component 119 , a serial-to-USB chip 120 and a USB interface 121 . Wherein, the antenna 118 is used to receive the capacitive digital signal sent by the antenna 115 in the slave wireless communication module 105 , and send the capacitive digital signal to the computer 102 through the serial port to USB chip 120 and the USB interface 121 in turn. The computer 102 calculates according to the received capacitance digital signal, and finally obtains the water depth of the measured water.

In an example of the present invention, different amounts of water are injected into the insulating container 107, and the water depth is measured with the device of the present invention, and at the same time, the actual water depth in the container is accurately obtained by weighing with a precision electronic balance, and the two are compared and measured. The results are shown in Figure 5. In all tests, the average error is only 0.27mm, and the maximum error is only 0.71mm.

The experimental high-precision wireless digital water depth sensor system of the embodiment of the present invention has the following advantages:

1. Retain the advantages of capacitive water depth detector, high measurement accuracy, fast measurement speed, and can be used for water depth detection of fluctuating and unstable water flow;

2. Only one metal wire is in contact with water, which has little influence on water flow;

3. The use of hydrophobic coatings reduces the additional error caused by contact angle hysteresis;

4. The sensor is highly digitized to avoid interference and unnecessary errors caused by analog-to-digital conversion;

5. The sensor is wireless, which saves the trouble of laying cables, and can measure the water depth data of multiple locations at the same time through one host and multiple slaves;

6. Through the supporting software on the computer, it is convenient to obtain and store the real-time data of the sensor, and even perform some simple data processing. The invention has high precision, little hindrance to water flow, fast measurement speed, high degree of digitization, can realize wireless data transmission, and can be used for water depth data collection in related experiments such as hydraulics.

In addition, other configurations and functions of the experimental high-precision wireless digital water depth sensor system of the embodiment of the present invention are known to those skilled in the art, and will not be repeated in order to reduce redundancy.

In the description of this specification, descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the invention is defined by the claims and their equivalents.

Claims (6)

1. A high-precision wireless digital water depth sensor system for experiments, is characterized in that, comprising: The slave includes a sensitive element, a capacitive digital-to-analog conversion module and a slave wireless communication module. The sensitive element includes an insulating container, a metal plate fixed on the outer wall of the insulating container, and a metal plate inserted into the insulating container. A metal wire, one end of the metal wire is less than a preset distance from the inner bottom wall of the insulating container, and the metal wire and the electrode plate are connected to the capacitance digital-to-analog conversion module; the capacitance digital-to-analog conversion module, It is used to convert the capacitance value between the metal wire and the electrode plate into a capacitance digital signal when introducing the measured water into the insulating container, and send the capacitance digital signal to the slave wireless A communication module; the slave wireless communication module is used to send the capacitive digital signal; A host, the host includes a host wireless communication module and a computer, the host wireless communication module is used to receive the capacitive digital signal sent by the slave wireless communication module, and the computer is connected to the host communication module for The water depth of the measured water is obtained according to the capacitance digital signal. 2. The experimental high-precision wireless digital water depth sensor system according to claim 1, characterized in that a hydrophobic coating is coated on the inner sidewall of the insulating container corresponding to the metal plate. 3. experiment according to claim 2 uses high-precision wireless digital water depth sensor system, is characterized in that, described hydrophobic coating is SiO ₂ nano-coating. 4. The experimental high-precision wireless digital water depth sensor system according to claim 1, wherein the metal plate is a red copper plate. 5. The experimental high-precision wireless digital water depth sensor system according to claim 1, wherein the preset distance is 5 mm. 6. The experimental high-precision wireless digital water depth sensor system according to claim 1 or 4, wherein the capacitance digital-to-analog conversion module includes a reference capacitance and a capacitance-to-digital conversion chip, and the metal wire and the metal plate All are connected with the capacitance-to-digital conversion chip, the reference capacitance is a monolithic capacitance, and the capacitance-to-digital conversion chip is the PCAP01 capacitance-to-digital conversion chip of the German acam company.